It have reinstalled everything with the latest versions of today. I suppose the problem came during the adjustment of all the versions updates from the last couple of days. Thanks for your help.
So a tip for all, never use duplicated modules from other people.

The file is there and the test is working. Even the google screen pops up.

Hi,

I have setup the Pi4 (latested version) with a ReSpeaker4 as mic. When I ask ‘SmartMirror’ the google interface showsup and then it stops. I receive the following message;

[2020-04-12 07:54:43.762] [LOG] [HOTWORD] Detected: SMARTMIRROR
[2020-04-12 07:54:44.024] [LOG] [HOTWORD] After Recording: 8000
[2020-04-12 07:54:44.271] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:44.287] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:44.512] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:44.526] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:44.765] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:44.780] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:45.035] [LOG] [HOTWORD] After Recording: 8000
[2020-04-12 07:54:45.265] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:45.276] [LOG] [HOTWORD] After Recording: 4000
[2020-04-12 07:54:46.509] [LOG] [HOTWORD] stops.
[2020-04-12 07:54:46.512] [LOG] [HOTWORD] After Recording finised. size: 48050
[2020-04-12 07:54:46.516] [LOG] [HOTWORD:B2W] WAV_FILE_CREATED: /home/pi/MagicMirror/modules/MMM-Hotword/temp/afterRecording.wav 48050
[2020-04-12 07:54:46.517] [LOG] [HOTWORD] Final Result: {
detected: true,
hotword: ‘SMARTMIRROR’,
file: ‘temp/afterRecording.wav’
}
[2020-04-12 07:54:47.085] [LOG] Whoops! There was an uncaught exception…
[2020-04-12 07:54:47.086] [ERROR] TypeError [ERR_INVALID_ARG_TYPE] [ERR_INVALID_ARG_TYPE]: The “path” argument must be of type string. Received type undefined
at validateString (internal/validators.js:107:11)
at Object.resolve (path.js:978:7)
at new ASSISTANT (/home/pi/MagicMirror/modules/MMM-AssistantMk2/components/assistant.js:29:28)
at Class.activateAssistant (/home/pi/MagicMirror/modules/MMM-AssistantMk2/node_helper.js:86:22)
at Class.socketNotificationReceived (/home/pi/MagicMirror/modules/MMM-AssistantMk2/node_helper.js:37:14)
at Socket. (/home/pi/MagicMirror/js/node_helper.js:113:11)
at Socket.emit (events.js:200:13)
at /home/pi/MagicMirror/node_modules/socket.io/lib/socket.js:528:12
at processTicksAndRejections (internal/process/task_queues.js:82:9)

Does anyone know how to solve this?
I allready tried to reinstall the complete Pi with a new version and all modules.